The Puffstalk is a small member of the Sporovid Family featured in Hey! Pikmin. Unlike the Puffstool, the Puffstalk is completely harmless and don't even go after Captain Olimar and his Pikmin when it see them.
The Puffstalk lives in holes located on a wall, it will stick its head out of different holes at a rapid pace and Olimar must predict its moves and launch Pikmin on it. The Puffstalk is not even on Olimar's way most of the time and the only reason to kill it is to retrieve the treasures it has since it is bent on collecting items charged with energy.
Hey! Pikmin Log
"A mysterious creature that likes to pop out of its next and then go right back in. It's bent on collecting energy-rich objects, but then, so am I, hmm?"